U.S. Pat. Nos. 3,227,831; 4,110,584 and 5,243,161 each describe electric disconnect switches having a viewing window in the front cover of the switch enclosure to visually ascertain the true condition of the switch contacts.
Each of the above-noted enclosures describes fastening devices that are used to attach the viewing window support to the enclosure door. The screws, rivets and other such metal fasteners require additional time and expense during manufacture and also limit the resistance of the enclosure to adverse outdoor environmental conditions. When such switch enclosures are submerged in water during in-process tests, there is a possibility that the water could seep by the openings that capture the metal fasteners.
One purpose of the invention is to provide an electric disconnect switch enclosure that doesn't utilize openings through the enclosure door to attach the viewing window.
An additional purpose of the invention is to describe an electric switch enclosure that includes a viewing window that is formed within the enclosure door in an automated assembly operation.